Methods for preparing thiocarbamylsulfenamide accelerators are described in U.S. Pat. No. 3,985,743. In one method an amine in a solvent is reacted with a bleach solution and carbon disulfide. At the end of the reaction, the water phase is separated from the organic phase containing the thiocarbamylsulfenamide reaction product. The organic phase is then washed with water. The solvent is removed as by flashing, distillation and the like and the remaining thiocarbamylsulfenamide reaction product is washed with a solvent such as an alcohol, centrifuged or filtered and dried.
It is desirable to eliminate some of these steps, especially the use of an expensive solvent that must be recovered and cleaned up before reuse, requiring expensive equipment and utilities as in processing steps, i.e., washing, filtration, drying, solvent recovery and purification and the like. Of equal importance is obtaining a thiocarbamylsulfenamide reaction product having better storage stability.
Thiocarbamylsulfenamides, N,N'-[thiocarbonylthio]dimorpholine, for example, are normally not very storage stable, particularly under high temperature storage conditions that are often encountered under summer conditions, or when exposed to other sources of heat. Under such conditions the thiocarbamylsulfenamide suffers degradation and a loss in activity. This results in slower cure rates and a decrease in scorch time. An incomplex process for preparing more stable thiocarbamylsulfenamides is desired.